This invention relates to a new chemical process for the preparation of 6-amino-2,2-dimethyl-3-(5-tetrazolyl)penam. Said 6-amino-2,2-dimethyl-3-(5-tetrazolyl)penam is valuable in the art as a chemical intermediate, since acylation thereof produces 6-acylamino-2,2-dimethyl-3-(5-tetrazolyl)penam compounds, which are useful antibacterial agents. The process of the invention involves treating certain 6-amino-2,2-dimethyl-3-(5-tetrazolyl)penam and 6-(protected amino)-2,2-dimethyl-3-(5-tetrazolyl)penam compounds, bearing an appropriate substituent at the 1-position of the tetrazole ring, with hydrogen fluoride.
It is known that 6-amino-2,2-dimethyl-3-(5-tetrazolyl)penam can be prepared from the same compounds which act as starting materials for the process of the instant invention, by treatment by trifluoroacetic acid. However, the instant process produces a higher yield of higher purity product, and it is considerably more convenient to operate when working on a large scale.